Supernovae searh at intermediate
z
II. Host galaxy morphology
J. Mendez (1,2), P. Ruiz-Lapuente (1), A. Balastegui (1),
G. Altavilla (1), M. Irwin (3), K. Shamanahe (4), C. Balland (5,6),
R. Pain (4), N. Walton (3)
1) Department of Astronomy, CER for Astrophysis, Partile Physis
and Cosmology, Univerisitat de Barelona, Diagonal 647, 08028,
Barelona, Spain
2) Isaa Newton Group of Telesopes, 38700 Santa Cruz de La Palma,
Islas Canarias, Spain
3) Institute of Astronomy, University of Cambridge, Madingley Road,
Cambridge. CB3 0HA, United Kingdom
4) LPNHE-IN2P3-CNRS-Universites Paris 6 et Paris 7, 4 plae
Jussieu, 75252 Paris Cedex 05 Frane
5) Institut d'Astrophysique Spatiale, B^
atiment 121, Universite Paris 11,
91405 Orsay Cedex, Frane
6) Universite Paris Sud, IAS-CNAS, B^
atiment 121, Orsay Cedex,
Frane
We disuss the host galaxy morphology of the 8 supernovae (SNe)
disovered as a part of the International Time Programme (ITP) projet \
and from Supernovae, and the physis of Supernovae Explosions" at the European Northern Observatory (ENO). Identiation of the SN host galaxies was
performed exploiting both imaging and spetrosopi failities at ENO. The relation between the SN type and the host galaxy morphology is investigated.
The study of the supernovae searh at medium and low redshift is also extended
here to the analysis of kinematis and abundane tomography. The expansion
veloities of the ejeta measured for eah normal SNe Ia are found to be within
the typial veloity dispersion for their epoh. Meanwhile, the sub-luminous SN
2002lk SiII expansion veloity is signiantly higher than that of SN 1991bg at
maximum, meaning that the observed epoh is a few days before maximum.
Abstrat.
1.
Galaxy morphology
Spetrosopi observation were arried out using the Intermediate dispersion
Spetrograph and Imaging System (ISIS) mounted at the WHT. From the analysis of the galaxy spetra, though ontaminated by the SN, we an disriminate
between spheroidal (elliptial and lentiular) and spiral galaxies. In the analysed
SN sample only the morphologies of a few host galaxies an be easily identied
by visual inspetion (see Fig.1, 2). The results are summarised in Table 1. This
study will be presented in details in a forthoming paper but we an already
note that the peuliar sub-luminous SN 2002lk, similar to SN1991bg, exploded
in a late-type galaxy while sub-luminous SNe, assoiated with an older stellar
population, are usually expeted in early-type galaxies (Howell 2001).
1
2
Mendez et al.
Figure 1. SN 2002lq host galaxy image (left panel) and spetrum (right
panel). The SN position is marked by an arrow. The SN spetrum shows
numerous galaxy features (Balmer series lines are learly visible). Both spetrosopy and imaging are onsistent with a fae-on spiral galaxy.
Figure 2. SN 2002lk host galaxy image (left panel) and spetrum (right
panel). The SN position is marked by an arrow. The SN spetrum shows a
few galaxy features (due to the high brightness of the SN, the only galaxy
lines learly identied are H , nitrogen and sulphur lines). A deep sodium
absorption is visible too. Spetrosopy and the absorption lane visible in the
imaging suggest that this is an edge-on spiral galaxy.
Table 1.
SN
name
2002li
2002lj
2002lp
2002lq
2002lr
2002lk
2002ln
2002lo
z
0.329
0.180
0.144
0.269
0.255
0.033
0.138
0.136
Host galaxy summary.
SN
Type
Ia
Ia
Ia
Ia
Ia
Ia pe.
II
II
Galaxy
Type
Spiral
Spheroidal
Spiral
Spiral
Spiral?
Spiral
Spiral
Spiral
Oset
from nuleus
0".1 W 0".2 S
0".2 W
0".2 E 2".0 N
4".5 E 0".7 S
3".0 S
0".7 W 0".2 N
1".1 W 8".3 S
0".6 E 1".3 S
Identied lines
H , H , HÆ , [SII℄, [NII℄, [OIII℄, [OII℄
H , H , H , [OII℄
H , H , H , HÆ , H , H , H , [SII℄, [OIII℄
H , [SII℄, [NII℄, [NeV℄
H , [SII℄, [NII℄, NaD
H , H , H , H , [SII℄
H , H , H , [NII℄, [OIII℄, [OII℄
Host Galaxy Morphology
Table 2.
Expansion veloities for CaII (3950
A) and SiII (6355
A) lines.
Objet
name
SN
SN
SN
SN
SN
SN
2.
3
2002li
2002lj
2002lp
2002lq
2002lr
2002lk
Expansion veloity Expansion veloity
CaII (km s 1 )
SiII (km s 1 )
17200500
12300300
13800900
189001400
12800300
8900300
10400400
8600400
14500500
Expansion of the ejeta
Expansion veloities for CaII (3950
A) and SiII (6355
A) lines have been measured
for eah SNe Ia, whenever the lines were present and well dened in the spetra.
A summary of the results is shown in table 2.
The unertainty in expansion veloity is measured by square summing the
standard deviation of several measurements, and adding to that an error in
redshift of 0.001. The unertainty in the epoh, respetive to maximum, when
measured with spetra omparison it is ommonly assumed to be approximately
of 2 days (Riess et al. 1997).
Figure 3 shows the expansion veloity, for CaII (3950
A) and SiII (6355
A)
lines, versus epoh from maximum, plotted for all SNe Ia. Referene evolution
traks are also inluded, orresponding to the reent well followed lose SNe Ia
SN 2002bo (Benetti et al. 2004). All data lie within the typial dispersion of
expansion veloities for normal SNe Ia. On the other hand, the sub-luminous
SNe Ia SN 2002lk SiII expansion veloity (14500 km s 1 ) is signiantly higher
than the veloity measured for SN 1991bg (9900 km s 1 ) at maximum, meaning
that probably the phase of SN 2002lk ould be younger than the previously
reported. Further results will be presented elsewhere.
Aknowledgments.
This researh was arried out within the International
Time Programme "Omega and Lambda from Supernovae and the Physis of
Supernova Explosions" at ENO.
Referenes
Benetti, S., Meikle, P., Stehle, M. et al. 2004, MNRAS, 348, 261
Howell, D. A., 2001, ApJ, 554, 193
Riess, A. G., Filippenko, A. V., Leonard, D. C. et al. 1997, ApJ, 114, 722
4
Mendez et al.
30000
SiII
CaII
SN 2002bo SiII
SN 2002bo CaII
−1
expansion velocity (km s )
25000
SN 2002lq
20000
SN 2002li
SN 2002lp
15000
SN 2002lj
SN 2002lk
10000
SN2002lp
SN 2002lj
SN 2002lr
SN 2002lr
5000
0
−10
−5
0
5
Epoch (days from maximum)
10
Figure 3. Expansion veloities for CaII (3950
A) and SiII (6355
A) lines as
a funtion of the epoh from maximum. It is also shown, as a referene, the
expansion veloities for SN 2002bo.
15